A comparative study of amplitude calibrations for the East Asia VLBI Network: A priori and template spectrum methods

被引：13

作者：

Cho, Ilje ^{[1
,2
]}

Jung, Taehyun ^{[1
,2
]}

Zhao, Guang-Yao ^{[1
]}

Akiyama, Kazunori ^{[3
,4
,5
]}

Sawada-Satoh, Satoko ^{[6
,7
]}

Kino, Motoki ^{[1
,5
,8
]}

Byun, Do-Young ^{[1
,2
,9
]}

Sohn, Bong Won ^{[1
,2
,9
]}

Shibata, Katsunori M. ^{[5
,10
]}

Hirota, Tomoya ^{[5
,10
]}

Niinuma, Kotaro ^{[11
]}

Yonekura, Yoshinori ^{[7
]}

Fujisawa, Kenta ^{[11
,12
]}

Oyama, Tomoaki ^{[5
]}

机构：

[1] Korea Astron & Space Sci Inst, Daedeok Daero 776, Daejeon 34055, South Korea

[2] Univ Sci & Technol, Gajeong Ro 217, Daejeon 34113, South Korea

[3] MIT, Haystack Observ, Route 40, Westford, MA 01886 USA

[4] Harvard Univ, Black Hole Initiat, 20 Garden St, Cambridge, MA 02138 USA

[5] Natl Astron Observ Japan, 2-21-1 Osawa, Mitaka, Tokyo 1818588, Japan

[6] Kagoshima Univ, Grad Sch Sci & Engn, 1-21-35 Korimoto, Kagoshima, Kagoshima 8900065, Japan

[7] Ibaraki Univ, Ctr Astron, 2-1-1 Bunkyo, Mito, Ibaraki 3108512, Japan

[8] Kogakuin Univ, Acad Support Ctr, 2665-1 Nakano, Hachioji, Tokyo 1920015, Japan

[9] Yonsei Univ, Yonsei Ro 50, Seoul 03722, South Korea

[10] SOKENDAI Grad Univ Adv Studies, Dept Astron Sci, Osawa 2-21-1, Mitaka, Tokyo 1818588, Japan

[11] Yamaguchi Univ, Grad Sch Sci & Technol Innovat, 1677-1 Yoshida, Yamaguchi, Yamaguchi 7538511, Japan

[12] Yamaguchi Univ, Res Inst Time Studies, 1677-1 Yoshida, Yamaguchi, Yamaguchi 7538511, Japan

来源：

PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN | 2017年 / 69卷 / 06期

基金：

日本学术振兴会; 美国国家科学基金会; 新加坡国家研究基金会;

关键词：

methods: data analysis; radio continuum: galaxies; radio lines: general; techniques: high angular resolution; techniques: interferometric; SUPERMASSIVE BLACK-HOLE; GALACTIC-CENTER; EVENT-HORIZON; MASER SOURCES; ASTERISK;

D O I：

10.1093/pasj/psx090

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We present the results of a comparative study of amplitude calibrations for the East Asia VLBI Network (EAVN) at 22 and 43 GHz using two different methods of an "a priori" and a "template spectrum", particularly on lower declination sources. Using observational data sets of early EAVN observations, we investigated the elevation-dependence of the gain values at seven stations of the KaVA (KVN and VERA Array) and three additional telescopes in Japan (Takahagi 32m, Yamaguchi 32 m, and Nobeyama 45m). By comparing the independently obtained gain values based on these two methods, we found that the gain values from each method were consistent within 10% at elevations higher than 10 degrees. We also found that the total flux densities of two images produced from the different amplitude calibrations were in agreement within 10% at both 22 and 43 GHz. By using the template spectrum method, furthermore, the additional radio telescopes can participate in KaVA (i.e., EAVN), giving a notable sensitivity increase. Therefore, our results will constrain the detailed conditions in order to measure the VLBI amplitude reliably using EAVN, and discuss the potential of possible expansion to telescopes comprising EAVN.

引用

页数：16